Hi all, recently im getting quote from contractor to do plaster ceiling with gypsum board.

He quoted me total 645sqft - RM7.5k with 8mm thick gypsum board for ceiling works together with emulsion white paint. plain ceiling works (flat type) w/o open light point.

Is it reasonable price? actually what difference nowadays between gypsum board and plaster ceiling board?? 

Any sifus here can give me advise? thanks!!